The Respiratory SystemStructures

Function of the Respiratory SystemFilters, warms, and humidifies the air we

breatheEnsures that oxygen is supplied TO…

…and carbon dioxide is removed FROM…the body’s cells

Influences speech productionMakes olfaction possible

StructuresDivided into Upper & Lower

Respiratory TractsContains Respiratory

mucosa:Specialized mucous

membrane that lines the respiratory tractSecretes sticky mucous

air purification mechanism. traps irritants such as dust and

pollenCilia on mucosal cells beat

upward, moving mucus to pharynx for removal.

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Histology: Pseudostratified Ciliated Columnar Epithelium with Goblet Cells (secrete mucus)

UPPER RESPIRATORY TRACTNoseNasal cavityPharynx

Naso-Oro-Laryngo-

LarynxMouthEustachian tubes

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NoseAir enters through external nares (nostrils)Nasal septum separates interior of nose into

two cavities (composed of ethmoid, quadrangular cartilage, vomer bone)

Nose warms and moistens inhaled air, contains organs of smell

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Nasal CavityLined by bone, mucous membrane

EthmoidMaxillaNasal bones

Warms, moistens, cleans airCilia trap microorganisms, materials

digestive systemTurbinates/conchae direct air to olfactory

gland_____________

SinusesFrontal, maxillary, sphenoidal, ethmoidal

sinuses drain into the noseProvide resonance for speechCan become inflamed (sinusitis)

CT ScansNormal vs. Chronic Sinusitis

Pharynx1. Nasopharynx- Mucous-secreting- Eustachian tubes- Adenoids2. Oropharynx- Digestive component- Tonsils3. Laryngopharynx larynx

Laryngopharynx

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Larynx (voice box)Composed mainly of cartilageBound by ligaments and musclesContains vocal cords that stretch across from

arytenoid to cricoid cartilagesChanges in tension changes pitch

Superior/anterior to larynx= epiglottis (closes off larynx during swallowing)

Anterior larynx=thyroid cartilage (largest, contains Adam’s apple)

Inferior larynx = cricoid cartilageHyoid bone located here

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Pathology of the Larynx

Vascular polyp w/ varices Laryngocele Leukoplakia & underlyingcarcinoma

LOWER RESPIRATORY TRACTLocated within the thoracic cavityIncludes the

TracheaBronchiLungs

BronchiolesAlveoli

Alveolar ducts Alveolar sacs

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Trachea4 ½ inches long, from

larynx to bronchiHeld open by 15-20 C-

shaped cartilaginous rings

Posterior muscleObstruction can cause

death w/in minutesCiliated to move mucus out- Smoking affects these

 

1 - Vocal cords2 - Thyroid cartilage3 - Cricoid cartilage4 - Tracheal cartileges5 - Balloon cuff

Remainder of Lower Respiratory TractR & L bronchi

Contain cartilage, smooth muscle

R is wider, shorter, more vertical

Divide into secondary and tertiary bronchi

Bronchioles (terminal and respiratory)

Lungs (alveolar ducts and sacs)

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Bronchi Bronchioles LungsTerminal bronchioles can dilate, constrictRespiratory bronchioles split into

2-11 alveolar ducts each 5-6 alveolar sacs each (look like bunches of

grapes)

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Alveolar Ducts Alveolar Sacs AlveoliAlveolar sacs are microscopic and come in

clustersMade up of alveoli:

site of gas exchange b/w air and bloodCoated with surfactant (reduces surface

tension, prevents them from collapsing)

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General Structure/Location of the LungsLungs: R—3 lobes, L—2 lobes (divide into

lobules)Apex: under clavicle Base: above diaphragmHeart in cardiac notch

Lobes and LobulesFunctional and structural:

Conducting portion Terminal bronchioles Clara cells – remove toxins

Respiratory portion Gas exchange occurs here

Type I alveolar cells – gas exchange Type II alveolar cells – secrete surfactant

Surfactant – reduces surface tension of lungs, allows easier expansion; prevents collapse of alveoli

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X-Ray: Right apex tumor

More on Lung StructurePleura: thin, moist, slippery

(serous) membrane Visceral pleura: covers the outer

surface of the lungs Parietal pleura: lines the inner

surface of the rib cage Produces pleural fluid-

intrapleural space must remain moist

Pathology: Pleurisy (pleuritis) – painful inflammation of the pleura

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Collapsed LungA.k.a. = pneumothoraxCaused when atmospheric

pressure enters the thoracic cavityNormally a partial vacuum

between ribcage and lungsTrauma introduces air,

which removes “suction” that keeps lungs inflated

Repaired by: chest tube